Project Blog 3/6/17

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Mackenzie, Annie, Nic

What problem we worked on

The problem we worked on was that Mrs. Garcia goes to Starbucks and asks for the hottest coffee and by the time she gets to her car, the drink has lost about 10 degrees (celsius). Now by the time she gets to school, the temperature of the cup has dropped about half the original temperature. Our cup is designed to keep 250 ml of water hot for a half hour.

The items we used were plastic, styrofoam, fleece, tinfoil and duct tape. All of these items are good materials because we needed insulators on the outside to stop heat from passing through the outside and we chose and conductor for the inside because the conductor on the inside so that the tin foil can warm the drink from the inside.

• Plastic makes a good insulator because it does not have free electrons within their structure. Free electrons are electrons that are unbound within the atomic or molecular matrix.
• Styrofoam is a good insulator because the plastic foam contains billions of trapped gas  because bubbles. Gases hinder heat conduction because their molecules are very far apart, make it difficult for the molecules to collide.

• Duct tape is a good insulator because it is made of rubber and the rubber is a good thermal insulator because it prevents electrons from coming through.

• Aluminum foil is a good thermal conductor because it radiates away all of the heat so rapidly that it cools off much faster than anything else.

• Fleece is a good thermal insulator because its fibers trap air inside it, making it difficult for heat to get in.

As you can see, all of these materials are extremely good materials. This is why we decided to use them.

How heat energy transferred worked in all our designs

We are using convection because the cup provides little insulation so a plastic lid helps reduce convection cooling of the coffee. Below is a diagram of our cup

   

Below are our pictures of our cup.                                                            

How our ideas changed:

Our original idea was to have a cup with styrofoam on the inside and duct tape holding it together. But that might drip, so we decided against it. Then we decided that we wanted something that would keep the coffee as warm as possible. Duct tape and styrofoam might not do the trick. So we decided to have nothing inside of the plastic cup and to put a styrofoam circle duct-taped to the outside. Then, we looked up which types of fabric insulates heat the best and we decided to create a wool sleeve. But after some research, we discovered that wool tends to “break” when wet. So we decided against wool. Our final sleeve is made of fleece. Fleece is made like wool and insulates heat well, but it is lighter and doesn’t sag or rip when wet. Fleece is better about being wet than wool. Originally, we wanted to hot-glue the sleeve to the cup, but then we decided when Ms. Garcia was washing it, she might want to wash the sleeve separately. So we made it reversible; one side solid purple, the other pineapple print. Then Nic said that maybe instead of just using insulators, maybe we could use a conductor! So Mackenzie added tin foil to the inside so that it would conduct more heat inside. But then we realized: How was Ms. Garcia to wash it? The tinfoil would get in the way, so we removed it.

Prototype Data Table

	Prototype	Styrofoam cup	Plastic cup
Original Temp.
Temp. After 10 min
Temp. After 20 min
Temp. After 30 min

Final Test Data Table

	Final cup
Original Temp.
Temp. After 10 min
Temp. After 20 min
Temp. After 30 min

Backward looking: In what ways have you gotten better at this kind of work?
I have gotten a lot better at working with a group over last and this year

Outward looking: Did you do your work the way other people did theirs? In what ways did you do it differently? In what ways was your work or process similar?

I looked at another group's work. They used a bottle instead of a cup, but we both put tin foil inside to keep the coffee hot. 

Inward looking: How do you feel about this piece of work? What parts of it do you particularly like? Dislike? Why? What did/do you enjoy about this piece or work?

I liked that we had to collaborate ideas with our team. 

Forward looking: What's one goal you would like to set for yourself for next time?

I want to focus more on the research first.